Difference between revisions of "Arduino notes"
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| + | == Arduino Wire Library == | ||
| + | |||
| + | 2018-05-21 - Monday, looking at /usr/share/arduino/libraries/Wire/utility/twi.c, routine twi_writeTo() error codes: | ||
| + | |||
| + | <pre> | ||
| + | 177 /* | ||
| + | 178 * Function twi_writeTo | ||
| + | 179 * Desc attempts to become twi bus master and write a | ||
| + | 180 * series of bytes to a device on the bus | ||
| + | 181 * Input address: 7bit i2c device address | ||
| + | 182 * data: pointer to byte array | ||
| + | 183 * length: number of bytes in array | ||
| + | 184 * wait: boolean indicating to wait for write or not | ||
| + | 185 * sendStop: boolean indicating whether or not to send a stop at the end | ||
| + | 186 * Output 0 .. success | ||
| + | 187 * 1 .. length to long for buffer | ||
| + | 188 * 2 .. address send, NACK received | ||
| + | 189 * 3 .. data send, NACK received | ||
| + | 190 * 4 .. other twi error (lost bus arbitration, bus error, ..) | ||
| + | 191 */ | ||
| + | 192 uint8_t twi_writeTo(uint8_t address, uint8_t* data, uint8_t length, uint8_t wait, uint8_t sendStop) | ||
| + | 193 { | ||
| + | 194 uint8_t i; | ||
| + | 195 | ||
| + | 196 // ensure data will fit into buffer | ||
| + | 197 if(TWI_BUFFER_LENGTH < length){ | ||
| + | 198 return 1; | ||
| + | 199 } | ||
| + | . | ||
| + | . | ||
| + | . | ||
| + | </pre> | ||
| + | |||
| + | |||
| + | |||
| + | According to the oscilloscope the I2C communications are running at about 192kHz, a little fast. Here is documentation at the Arduino site about setting the I2C clock rate: | ||
| + | |||
| + | * https://www.arduino.cc/en/Reference/WireSetClock . . . Wire.setClock() class method not found on localhost! | ||
| + | |||
| + | Another place where SCL frequency may be set . . . | ||
| + | |||
| + | <pre> | ||
| + | user@localhost:/usr/share/arduino/libraries/Wire$ grep -nr lock ./* | ||
| + | ./Wire.cpp:84: // perform blocking read into buffer | ||
| + | ./Wire.cpp:139: // transmit buffer (blocking) | ||
| + | ./utility/twi.c:85: SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR)) | ||
| + | ./utility/twi.c:467: // sends ack and stops interface for clock stretching | ||
| + | </pre> | ||
| + | |||
| + | |||
| + | 2022-06-13 | ||
| + | |||
| + | OpenMV IDE and Arduino Nano: | ||
| + | <ul> | ||
| + | * https://blog.arduino.cc/2021/08/24/power-of-python-for-arduino-nano-rp2040-connect-and-nano-33-ble/ | ||
| + | </ul> | ||
| + | |||
| + | |||
| + | <!-- comment --> | ||
| + | |||
| + | == References == | ||
| + | |||
| + | <!-- comment --> | ||
| + | |||
| + | |||
| + | |||
| + | |||
| + | <!-- comment --> | ||
<!-- comment --> | <!-- comment --> | ||
Latest revision as of 20:08, 13 June 2022
Getting started:
- https://playground.arduino.cc/Learning/CommandLine . . . mentions PlatformIO "ecosystem" and specific Linux ready command line tools for working with Arduino
- https://www.youtube.com/watch?v=qAM2S27FWAI . . . avr-dude and related tools can program Arduino Uno boards
- https://playground.arduino.cc/OpenBSD/CLI . . . Arduino development work on OpenBSD systems
The ATMEGA328P processor used in Arduino Uno boards:
- http://www.microchip.com/wwwproducts/en/ATmega328p . . . the ATMEGA328P processor used in Arduino Uno boards
Specific Arduino projects:
- https://www.hackster.io/niesse/water-level-ultrasonic-sensor-with-lorawan-c2cf55
- https://www.arduino.cc/en/Tutorial/HelloWorld
FreeRTOS port to Arduino:
Arduino Wire Library
2018-05-21 - Monday, looking at /usr/share/arduino/libraries/Wire/utility/twi.c, routine twi_writeTo() error codes:
177 /*
178 * Function twi_writeTo
179 * Desc attempts to become twi bus master and write a
180 * series of bytes to a device on the bus
181 * Input address: 7bit i2c device address
182 * data: pointer to byte array
183 * length: number of bytes in array
184 * wait: boolean indicating to wait for write or not
185 * sendStop: boolean indicating whether or not to send a stop at the end
186 * Output 0 .. success
187 * 1 .. length to long for buffer
188 * 2 .. address send, NACK received
189 * 3 .. data send, NACK received
190 * 4 .. other twi error (lost bus arbitration, bus error, ..)
191 */
192 uint8_t twi_writeTo(uint8_t address, uint8_t* data, uint8_t length, uint8_t wait, uint8_t sendStop)
193 {
194 uint8_t i;
195
196 // ensure data will fit into buffer
197 if(TWI_BUFFER_LENGTH < length){
198 return 1;
199 }
.
.
.
According to the oscilloscope the I2C communications are running at about 192kHz, a little fast. Here is documentation at the Arduino site about setting the I2C clock rate:
- https://www.arduino.cc/en/Reference/WireSetClock . . . Wire.setClock() class method not found on localhost!
Another place where SCL frequency may be set . . .
user@localhost:/usr/share/arduino/libraries/Wire$ grep -nr lock ./* ./Wire.cpp:84: // perform blocking read into buffer ./Wire.cpp:139: // transmit buffer (blocking) ./utility/twi.c:85: SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR)) ./utility/twi.c:467: // sends ack and stops interface for clock stretching
2022-06-13
OpenMV IDE and Arduino Nano:
